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5 Conclusions
We present a new heat-pulse-based method, the Double-Ratio Method (DRM), to calculate sap velocity in woody plants. We demonstrate both theoretically and experimentally that the DRM can effectively measure a broader range of sap velocities than other common heat-pulse based methods. Like an earlier approach that combined the HRM and CHPM, the DRM computes two distinct estimates of sap velocity at each time point; however, the DRM has several advantages over the combination of the HRM and CHPM, including a theoretical basis for selecting between the two velocity estimates and identifying the optimal times for averaging data, and a reduced sensitivity to noise at high velocities.
Acknowledgements
This work was supported by the Australian Research Council (LP130100183), the International Wheat Yield Partnership (IWYP, project 89) through a grant from the Grains Research and Development Corporation (GRDC, US00082), the National Science Foundation (Awards #1557906 and 1951244), Almond Board of California and the USDA National Institute of Food and Agriculture, Hatch project 1016439.